1. Field of the Invention
This invention relates to a method for the manufacture of a composite material containing ceramic particles dispersed in a metal matrix.
2. Description of the Prior Art
A number of techniques have been heretofore available for the manufacture of a composite material containing dispersed particles. A technique which resorts to solidification is one of these techniques.
The solidification technique is based on a procedure which comprises dispersing particles composed of materials such as ceramics in a mass of molten metal, pouring the resultant composite in a cast, and causing the composite to solidify therein. The most difficult problems encountered in the solidification technique are how keep the particles uniformly dispersed in the molten metal and how to keep the particles in the dispersed state in the molten metal during the solidification of the composite. Now, typical methods embodying the solidification technique will be described below. In one method the metal is melted to a point where the produced molten metal still contains within the liquid state (molten metal) a portion of the metal in its non-molten state. The metal, therefore, assumes a high viscosity such that when the ceramic particles are incorporated therein, the molten metal will not easily release the ceramic particles. Accordingly the ceramic particles are dispersed in the state described above in the molten metal, solidifying the resultant composite (September, 1976 issue of "Metallurgical Transaction B, Volume 7B, 443-450).
Another method contemplates adding to the molten metal an alloy element capable of increasing the viscosity of the molten metal. This allows the molten metal to assume a state capable of readily keeping the incorporated ceramic particles dispersed fast therein (Glossary of Manuscripts for Lectures at the 60th Spring Meeting of Japan Light Metal Study Society held in May 1981).
Yet another method contemplates applying a metal plate to the surface of the ceramic particles thereby enabling the particles to be amply wetted with the molten metal and consequently dispersed advantageously therein (1969 issue of AFS Transaction, pp 402-406). The above methods involve complicated processes and afford products of stable quality only with difficulty. These methods have been impractical for the actual manufacture of a composite material particularly when the particles are of a type not readily intermingled with the molten metal.
The object of this invention is to provide a method for the manufacture of a composite containing therein dispersed particles, which method permits easy dispersion of the particles in the molten metal and permits manufacture of a composite material of stable quality.